One of the most important concerns of scientists and practitioners engaged in substance abuse research and treatment is understanding factors related to the transition of initial drug use to compulsive drug taking. A greater understanding of the behavioral, neurochemical and pharmacologic variables associated with this catastrophic transition is important to the design and implementation of improved treatment strategies. The "Biological Vulnerability to Drug Addiction" is the title and focus of the 1999 FASEB Summer Research Conference on Drug Abuse to be held August 1- 6, 1999, at Copper Mountain, Colorado. The forum of the Summer Research Conferences provides an atmosphere that is conducive for presentation of up-to-date research findings to a broad-based research community interested in these issues providing a quality interactive environment for examining critical problems facing the field. A particular emphasis is the interface of basic science and clinical research to facilitate information transfer from the bench to clinical practice as well as to make clinical needs known to those in the basic sciences. To ensure an interactive atmosphere attendees will be limited to 155 participants, including 49 conference faculty. The conference will consist of six scientific sessions entitled, State of the Art: Current Issues, Neuroanatomical Substrates, Genetic Factors, Neuroendocrine Factors and Stress, Neurobehavioral Factors and Medication Development and Treatment. The format will include invited presentations from prominent and young investigators, a poster session and technical workshops. The atmosphere will be conducive for a productive exchange of information and new ideas. Funds are requested to support travel awards for six predoctoral students, six postdoctoral students and six young investigators. Availability of these awards will be advertised in journals, society newsletters and websites. Two panels of three scientists, including one of the conference organizers, will review all applications and make the award decisions. These decisions will be based on a completed application form, an abstract of research to be presented at the meeting as a poster and two letters of reference. Additional funds are requested to partially defray the cost of travel and attendance for 30 of the 49 conference faculty. Research on issues related to drug abuse vulnerability continues to progress and develop at a rapid rate. Critical data from significant studies have recently become available which can be used to develop more sophisticated approaches than those previously developed. Thus, there is a critical need to provide a form for communication amongst the diverse group of scientists involved in this research endeavor. Based on the success of the previous two meetings the FASEB Summer Research Conference provides an environment likely to result in new and novel collaborative approaches to understanding factors related to vulnerability to drug abuse.